org.apache.hadoop.hbase.util
Class Bytes

java.lang.Object
  org.apache.hadoop.hbase.util.Bytes

public class Bytes
extends Object

Utility class that handles byte arrays, conversions to/from other types, comparisons, hash code generation, manufacturing keys for HashMaps or HashSets, etc.

Nested Class Summary

static class

Bytes.ByteArrayComparator Byte array comparator class.

Field Summary

static Comparator<byte[]>	BYTES_COMPARATOR Pass this to TreeMaps where byte [] are keys.
static org.apache.hadoop.io.RawComparator<byte[]>	BYTES_RAWCOMPARATOR Use comparing byte arrays, byte-by-byte
static int	ESTIMATED_HEAP_TAX Estimate of size cost to pay beyond payload in jvm for instance of byte [].
static int	SIZEOF_BOOLEAN Size of boolean in bytes
static int	SIZEOF_BYTE Size of byte in bytes
static int	SIZEOF_CHAR Size of char in bytes
static int	SIZEOF_DOUBLE Size of double in bytes
static int	SIZEOF_FLOAT Size of float in bytes
static int	SIZEOF_INT Size of int in bytes
static int	SIZEOF_LONG Size of long in bytes
static int	SIZEOF_SHORT Size of short in bytes

Constructor Summary

Bytes()

Method Summary

static byte[]	add(byte[] a, byte[] b)
static byte[]	add(byte[] a, byte[] b, byte[] c)
static int	binarySearch(byte[][] arr, byte[] key, int offset, int length, org.apache.hadoop.io.RawComparator<byte[]> comparator) Binary search for keys in indexes.
static long	bytesToVint(byte[] buffer)
static int	compareTo(byte[] left, byte[] right)
static int	compareTo(byte[] b1, int s1, int l1, byte[] b2, int s2, int l2)
static boolean	equals(byte[] left, byte[] right)
static int	hashCode(byte[] b)
static int	hashCode(byte[] b, int length)
static byte[]	head(byte[] a, int length)
static byte[]	incrementBytes(byte[] value, long amount) Bytewise binary increment/deincrement of long contained in byte array on given amount.
static Integer	mapKey(byte[] b)
static Integer	mapKey(byte[] b, int length)
static byte[]	padHead(byte[] a, int length)
static byte[]	padTail(byte[] a, int length)
static int	putByte(byte[] bytes, int offset, byte b) Write a single byte out to the specified byte array position.
static int	putBytes(byte[] tgtBytes, int tgtOffset, byte[] srcBytes, int srcOffset, int srcLength) Put bytes at the specified byte array position.
static int	putDouble(byte[] bytes, int offset, double d)
static int	putFloat(byte[] bytes, int offset, float f)
static int	putInt(byte[] bytes, int offset, int val) Put an int value out to the specified byte array position.
static int	putLong(byte[] bytes, int offset, long val) Put a long value out to the specified byte array position.
static int	putShort(byte[] bytes, int offset, short val) Put a short value out to the specified byte array position.
static byte[]	readByteArray(DataInput in) Read byte-array written with a WritableableUtils.vint prefix.
static byte[]	readByteArrayThrowsRuntime(DataInput in) Read byte-array written with a WritableableUtils.vint prefix.
static long	readVLong(byte[] buffer, int offset) Reads a zero-compressed encoded long from input stream and returns it.
static byte[][]	split(byte[] a, byte[] b, int num) Split passed range.
static byte[]	tail(byte[] a, int length)
static byte	toBinaryFromHex(byte ch) Takes a ASCII digit in the range A-F0-9 and returns the corresponding integer/ordinal value.
static boolean	toBoolean(byte[] b)
static byte[][]	toByteArrays(byte[] column)
static byte[][]	toByteArrays(String column)
static byte[][]	toByteArrays(String[] t)
static byte[]	toBytes(boolean b) Convert a boolean to a byte array.
static byte[]	toBytes(ByteBuffer bb) Returns a new byte array, copied from the passed ByteBuffer.
static byte[]	toBytes(double d)
static byte[]	toBytes(float f)
static byte[]	toBytes(int val) Convert an int value to a byte array
static byte[]	toBytes(long val) Convert a long value to a byte array
static byte[]	toBytes(short val) Convert a short value to a byte array
static byte[]	toBytes(String s) Converts a string to a UTF-8 byte array.
static byte[]	toBytesBinary(String in)
static double	toDouble(byte[] bytes)
static double	toDouble(byte[] bytes, int offset)
static float	toFloat(byte[] bytes) Presumes float encoded as IEEE 754 floating-point "single format"
static float	toFloat(byte[] bytes, int offset) Presumes float encoded as IEEE 754 floating-point "single format"
static int	toInt(byte[] bytes) Converts a byte array to an int value
static int	toInt(byte[] bytes, int offset) Converts a byte array to an int value
static int	toInt(byte[] bytes, int offset, int length) Converts a byte array to an int value
static long	toLong(byte[] bytes) Converts a byte array to a long value
static long	toLong(byte[] bytes, int offset) Converts a byte array to a long value
static long	toLong(byte[] bytes, int offset, int length) Converts a byte array to a long value
static short	toShort(byte[] bytes) Converts a byte array to a short value
static short	toShort(byte[] bytes, int offset) Converts a byte array to a short value
static short	toShort(byte[] bytes, int offset, int length) Converts a byte array to a short value
static String	toString(byte[] b)
static String	toString(byte[] b, int off, int len)
static String	toString(byte[] b1, String sep, byte[] b2)
static String	toStringBinary(byte[] b)
static String	toStringBinary(byte[] b, int off, int len)
static byte[]	vintToBytes(long vint)
static int	writeByteArray(byte[] tgt, int tgtOffset, byte[] src, int srcOffset, int srcLength) Write byte-array from src to tgt with a vint length prefix.
static void	writeByteArray(DataOutput out, byte[] b) Write byte-array with a WritableableUtils.vint prefix.
static void	writeByteArray(DataOutput out, byte[] b, int offset, int length) Write byte-array to out with a vint length prefix.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SIZEOF_BOOLEAN

public static final int SIZEOF_BOOLEAN

Size of boolean in bytes

See Also:

Constant Field Values

SIZEOF_BYTE

public static final int SIZEOF_BYTE

Size of byte in bytes

See Also:

Constant Field Values

SIZEOF_CHAR

public static final int SIZEOF_CHAR

Size of char in bytes

See Also:

Constant Field Values

SIZEOF_DOUBLE

public static final int SIZEOF_DOUBLE

Size of double in bytes

See Also:

Constant Field Values

SIZEOF_FLOAT

public static final int SIZEOF_FLOAT

Size of float in bytes

See Also:

Constant Field Values

SIZEOF_INT

public static final int SIZEOF_INT

Size of int in bytes

See Also:

Constant Field Values

SIZEOF_LONG

public static final int SIZEOF_LONG

Size of long in bytes

See Also:

Constant Field Values

SIZEOF_SHORT

public static final int SIZEOF_SHORT

Size of short in bytes

See Also:

Constant Field Values

ESTIMATED_HEAP_TAX

public static final int ESTIMATED_HEAP_TAX

Estimate of size cost to pay beyond payload in jvm for instance of byte []. Estimate based on study of jhat and jprofiler numbers.

See Also:

Constant Field Values

BYTES_COMPARATOR

public static Comparator<byte[]> BYTES_COMPARATOR

Pass this to TreeMaps where byte [] are keys.

BYTES_RAWCOMPARATOR

public static org.apache.hadoop.io.RawComparator<byte[]> BYTES_RAWCOMPARATOR

Use comparing byte arrays, byte-by-byte

Constructor Detail

Bytes

public Bytes()

Method Detail

readByteArray

public static byte[] readByteArray(DataInput in)
                            throws IOException

Read byte-array written with a WritableableUtils.vint prefix.

Parameters:

in - Input to read from.

Returns:

byte array read off in

Throws:

IOException

readByteArrayThrowsRuntime

public static byte[] readByteArrayThrowsRuntime(DataInput in)

Read byte-array written with a WritableableUtils.vint prefix. IOException is converted to a RuntimeException.

Parameters:

in - Input to read from.

Returns:

byte array read off in

writeByteArray

public static void writeByteArray(DataOutput out,
                                  byte[] b)
                           throws IOException

Write byte-array with a WritableableUtils.vint prefix.

Parameters:

out -

b -

Throws:

IOException

writeByteArray

public static void writeByteArray(DataOutput out,
                                  byte[] b,
                                  int offset,
                                  int length)
                           throws IOException

Write byte-array to out with a vint length prefix.

Parameters:

out -

b -

offset -

length -

Throws:

IOException

writeByteArray

public static int writeByteArray(byte[] tgt,
                                 int tgtOffset,
                                 byte[] src,
                                 int srcOffset,
                                 int srcLength)

Write byte-array from src to tgt with a vint length prefix.

Parameters:

tgt -

tgtOffset -

src -

srcOffset -

srcLength -

Returns:

New offset in src array.

putBytes

public static int putBytes(byte[] tgtBytes,
                           int tgtOffset,
                           byte[] srcBytes,
                           int srcOffset,
                           int srcLength)

Put bytes at the specified byte array position.

Parameters:

tgtBytes - the byte array

tgtOffset - position in the array

srcBytes - byte to write out

srcOffset -

srcLength -

Returns:

incremented offset

putByte

public static int putByte(byte[] bytes,
                          int offset,
                          byte b)

Write a single byte out to the specified byte array position.

Parameters:

bytes - the byte array

offset - position in the array

b - byte to write out

Returns:

incremented offset

toBytes

public static byte[] toBytes(ByteBuffer bb)

Returns a new byte array, copied from the passed ByteBuffer.

Parameters:

bb - A ByteBuffer

Returns:

the byte array

toString

public static String toString(byte[] b)

Parameters:

b - Presumed UTF-8 encoded byte array.

Returns:

String made from b

toString

public static String toString(byte[] b1,
                              String sep,
                              byte[] b2)

toString

public static String toString(byte[] b,
                              int off,
                              int len)

Parameters:

b - Presumed UTF-8 encoded byte array.

off -

len -

Returns:

String made from b

toStringBinary

public static String toStringBinary(byte[] b)

toStringBinary

public static String toStringBinary(byte[] b,
                                    int off,
                                    int len)

toBinaryFromHex

public static byte toBinaryFromHex(byte ch)

Takes a ASCII digit in the range A-F0-9 and returns the corresponding integer/ordinal value.

Parameters:

ch - The hex digit.

Returns:

The converted hex value as a byte.

toBytesBinary

public static byte[] toBytesBinary(String in)

toBytes

public static byte[] toBytes(String s)

Converts a string to a UTF-8 byte array.

Parameters:

s -

Returns:

the byte array

toBytes

public static byte[] toBytes(boolean b)

Convert a boolean to a byte array.

Parameters:

b -

Returns:

b encoded in a byte array.

toBoolean

public static boolean toBoolean(byte[] b)

Parameters:

b -

Returns:

True or false.

toBytes

public static byte[] toBytes(long val)

Convert a long value to a byte array

Parameters:

val -

Returns:

the byte array

toLong

public static long toLong(byte[] bytes)

Converts a byte array to a long value

Parameters:

bytes -

Returns:

the long value

toLong

public static long toLong(byte[] bytes,
                          int offset)

Converts a byte array to a long value

Parameters:

bytes -

offset -

Returns:

the long value

toLong

public static long toLong(byte[] bytes,
                          int offset,
                          int length)

Converts a byte array to a long value

Parameters:

bytes -

offset -

length -

Returns:

the long value

putLong

public static int putLong(byte[] bytes,
                          int offset,
                          long val)

Put a long value out to the specified byte array position.

Parameters:

bytes - the byte array

offset - position in the array

val - long to write out

Returns:

incremented offset

toFloat

public static float toFloat(byte[] bytes)

Presumes float encoded as IEEE 754 floating-point "single format"

Parameters:

bytes -

Returns:

Float made from passed byte array.

toFloat

public static float toFloat(byte[] bytes,
                            int offset)

Presumes float encoded as IEEE 754 floating-point "single format"

Parameters:

bytes -

offset -

Returns:

Float made from passed byte array.

putFloat

public static int putFloat(byte[] bytes,
                           int offset,
                           float f)

Parameters:

bytes -

offset -

f -

Returns:

New offset in bytes

toBytes

public static byte[] toBytes(float f)

Parameters:

f -

Returns:

the float represented as byte []

toDouble

public static double toDouble(byte[] bytes)

Parameters:

bytes -

Returns:

Return double made from passed bytes.

toDouble

public static double toDouble(byte[] bytes,
                              int offset)

Parameters:

bytes -

offset -

Returns:

Return double made from passed bytes.

putDouble

public static int putDouble(byte[] bytes,
                            int offset,
                            double d)

Parameters:

bytes -

offset -

d -

Returns:

New offset into array bytes

toBytes

public static byte[] toBytes(double d)

Parameters:

d -

Returns:

the double represented as byte []

toBytes

public static byte[] toBytes(int val)

Convert an int value to a byte array

Parameters:

val -

Returns:

the byte array

toInt

public static int toInt(byte[] bytes)

Converts a byte array to an int value

Parameters:

bytes -

Returns:

the int value

toInt

public static int toInt(byte[] bytes,
                        int offset)

Converts a byte array to an int value

Parameters:

bytes -

offset -

Returns:

the int value

toInt

public static int toInt(byte[] bytes,
                        int offset,
                        int length)

Converts a byte array to an int value

Parameters:

bytes -

offset -

length -

Returns:

the int value

putInt

public static int putInt(byte[] bytes,
                         int offset,
                         int val)

Put an int value out to the specified byte array position.

Parameters:

bytes - the byte array

offset - position in the array

val - int to write out

Returns:

incremented offset

toBytes

public static byte[] toBytes(short val)

Convert a short value to a byte array

Parameters:

val -

Returns:

the byte array

toShort

public static short toShort(byte[] bytes)

Converts a byte array to a short value

Parameters:

bytes -

Returns:

the short value

toShort

public static short toShort(byte[] bytes,
                            int offset)

Converts a byte array to a short value

Parameters:

bytes -

offset -

Returns:

the short value

toShort

public static short toShort(byte[] bytes,
                            int offset,
                            int length)

Converts a byte array to a short value

Parameters:

bytes -

offset -

length -

Returns:

the short value

putShort

public static int putShort(byte[] bytes,
                           int offset,
                           short val)

Put a short value out to the specified byte array position.

Parameters:

bytes - the byte array

offset - position in the array

val - short to write out

Returns:

incremented offset

vintToBytes

public static byte[] vintToBytes(long vint)

Parameters:

vint - Integer to make a vint of.

Returns:

Vint as bytes array.

bytesToVint

public static long bytesToVint(byte[] buffer)

Parameters:

buffer -

Returns:

vint bytes as an integer.

readVLong

public static long readVLong(byte[] buffer,
                             int offset)
                      throws IOException

Reads a zero-compressed encoded long from input stream and returns it.

Parameters:

buffer - Binary array

offset - Offset into array at which vint begins.

Returns:

deserialized long from stream.

Throws:

IOException

compareTo

public static int compareTo(byte[] left,
                            byte[] right)

Parameters:

left -

right -

Returns:

0 if equal, < 0 if left is less than right, etc.

compareTo

public static int compareTo(byte[] b1,
                            int s1,
                            int l1,
                            byte[] b2,
                            int s2,
                            int l2)

Parameters:

b1 -

b2 -

s1 - Where to start comparing in the left buffer

s2 - Where to start comparing in the right buffer

l1 - How much to compare from the left buffer

l2 - How much to compare from the right buffer

Returns:

0 if equal, < 0 if left is less than right, etc.

equals

public static boolean equals(byte[] left,
                             byte[] right)

Parameters:

left -

right -

Returns:

True if equal

hashCode

public static int hashCode(byte[] b)

Parameters:

b -

Returns:

Runs WritableComparator.hashBytes(byte[], int) on the passed in array. This method is what Text and ImmutableBytesWritable use calculating hash code.

hashCode

public static int hashCode(byte[] b,
                           int length)

Parameters:

b -

length -

Returns:

Runs WritableComparator.hashBytes(byte[], int) on the passed in array. This method is what Text and ImmutableBytesWritable use calculating hash code.

mapKey

public static Integer mapKey(byte[] b)

Parameters:

b -

Returns:

A hash of b as an Integer that can be used as key in Maps.

mapKey

public static Integer mapKey(byte[] b,
                             int length)

Parameters:

b -

length -

Returns:

A hash of b as an Integer that can be used as key in Maps.

add

public static byte[] add(byte[] a,
                         byte[] b)

Parameters:

a -

b -

Returns:

New array that has a in lower half and b in upper half.

add

public static byte[] add(byte[] a,
                         byte[] b,
                         byte[] c)

Parameters:

a -

b -

c -

Returns:

New array made from a, b and c

head

public static byte[] head(byte[] a,
                          int length)

Parameters:

a -

length -

Returns:

First length bytes from a

tail

public static byte[] tail(byte[] a,
                          int length)

Parameters:

a -

length -

Returns:

Last length bytes from a

padHead

public static byte[] padHead(byte[] a,
                             int length)

Parameters:

a -

length -

Returns:

Value in a plus length prepended 0 bytes

padTail

public static byte[] padTail(byte[] a,
                             int length)

Parameters:

a -

length -

Returns:

Value in a plus length appended 0 bytes

split

public static byte[][] split(byte[] a,
                             byte[] b,
                             int num)

Split passed range. Expensive operation relatively. Uses BigInteger math. Useful splitting ranges for MapReduce jobs.

Parameters:

a - Beginning of range

b - End of range

num - Number of times to split range. Pass 1 if you want to split the range in two; i.e. one split.

Returns:

Array of dividing values

toByteArrays

public static byte[][] toByteArrays(String[] t)

Parameters:

t -

Returns:

Array of byte arrays made from passed array of Text

toByteArrays

public static byte[][] toByteArrays(String column)

Parameters:

column -

Returns:

A byte array of a byte array where first and only entry is column

toByteArrays

public static byte[][] toByteArrays(byte[] column)

Parameters:

column -

Returns:

A byte array of a byte array where first and only entry is column

binarySearch

public static int binarySearch(byte[][] arr,
                               byte[] key,
                               int offset,
                               int length,
                               org.apache.hadoop.io.RawComparator<byte[]> comparator)

Binary search for keys in indexes.

Parameters:

arr - array of byte arrays to search for

key - the key you want to find

offset - the offset in the key you want to find

length - the length of the key

comparator - a comparator to compare.

Returns:

index of key

incrementBytes

public static byte[] incrementBytes(byte[] value,
                                    long amount)
                             throws IOException

Bytewise binary increment/deincrement of long contained in byte array on given amount.

Parameters:

value - - array of bytes containing long (length <= SIZEOF_LONG)

amount - value will be incremented on (deincremented if negative)

Returns:

array of bytes containing incremented long (length == SIZEOF_LONG)

Throws:

IOException - - if value.length > SIZEOF_LONG